Now that the engine is running with no apparent fatal flaws I'm turning my attention to wiring the oil pressure sender gauge. The unit I have is a VDO 100 psi unit. To retain the dashboard warning light I'll need to also retain the sender unit that it is wired to.

In the photos below you'll see that there really is no room to add the new sender unit directly to the standard location - my oil filter lines are in the way.

My current intent is to run a flexible hose from block to T piece and at the T reinstall the original oil pressure switch for the dash light and also another short section of flexible hose to then mount the gauge sender unit in the location shown in the 2nd photo. (The 100PSI sender is apparently not available with connection for the warning light). The sender unit would then be clamped to the bolt that holds the fan belt guide bracket. That will keep it secure and will also earth / ground it.

So my two simple questions after that too long introduction are:1. Has anyone got a better idea than above (including "why bother"); and2. What thread is the standard fitting on the casting that the current sender unit fits into (1/8" NPT?).

Yes 1/8" npt.I'd purchase a 1/8" st 45° elbow and a long 1/8" grease gun hose. Make a cross drilled aluminum manifold with 1/8" npt in the end and 3 or 4 on top. Screw the 45 el into the original sender location. The hose into that and snake it behind the altenator. Mount the manifold to the left head.Put a rubber grommet around the oil dip stick pipe. You're losing precious cooling air.

Thanks for your reply. Given my remote oil filter lines I don't fancy my chances of being able to screw in an elbow. And am understandably reluctant to undo the oil filter lines for this - they are very very hard to get at with the engine in (backwards!).